Fluid-solid transition in hard hyper-sphere systems

In this work we present a numerical study, based on molecular dynamics simulations, to estimate the freezing point of hard spheres and hypersphere systems in dimension D = 4, 5, 6 and 7. We have studied the changes of the Radial Distribution Function (RDF) as a function of density in the coexistence region. We started our simulations from crystalline states with densities above the melting point, and moved down to densities in the liquid state below the freezing point. For all the examined dimensions (including D = 3) it was observed that the height of the first minimum of the RDF changes in an almost continuous way around the freezing density and resembles a second order phase transition. With these results we propose a numerical method to estimate the freezing point as a function of the dimension D using numerical fits and semiempirical approaches. We find that the estimated values of the freezing point are very close to previously reported values from simulations and theoretical approaches up to D = 6 reinforcing the validity of the proposed method. This was also applied to numerical simulations for D = 7 giving new estimations of the freezing point for this dimensionality.Comment: 13 pages, 10 figure

Small smooth units (‘young’ lavas?) abutting lobate scarps on Mercury

We have identified small units abutting, and so stratigraphy younger than, lobate scarps. This post dates the end of large scale smooth plains formation at the onset of global contraction. This elaborates the history of volcanism on Mercury

Seasonal Survival of Adult Female Mottled Ducks

The mottled duck (Anas fulgivula) is a non‐migratory duck dependent on coastal habitats to meet all of its life cycle requirements in the Western Gulf Coast (WGC) of Texas and Louisiana, USA. This population of mottled ducks has experienced a moderate decline during the past 2 decades. Adult survival has been identified as an important factor influencing population demography. Previous work based on band‐recovery data has provided only annual estimates of survival. We assessed seasonal patterns of female mottled duck survival from 2009 to 2012 using individuals marked with satellite platform transmitter terminals (PTTs). We used temperature and movement sensors within each PTT to indicate potential mortality events. We estimated cumulative weekly survival and ranked factors influential in patterns of mortality using known‐fate modeling in Program MARK. Models included 4 predictors: week; hunting and non‐hunting periods; biological periods defined as breeding, brooding, molt, and pairing; and mass at time of capture. Models containing hunt periods, during and outside the mottled duck season, comprised essentially 100% of model weights where both legal and illegal harvest had a negative influence on mottled duck survival. Survival rates were low during 2009–2011 (12–38% annual rate of survival), when compared with the long‐term banding average of 53% annual survival. During 2011, survival of female mottled ducks was the lowest annual rate (12%) ever documented and coincided with extreme drought. Management actions maximizing the availability of wetlands and associated upland habitats during hunting seasons and drought conditions may increase adult female mottled duck survival. © 2017 The Authors. Journal of Wildlife Management Published by Wiley Periodicals, Inc. on behalf of The Wildlife Society

Potential Identification of sublimation-driven downslope mass movement on Mercury

We have identified a further example of mass movement, in addition to the previously identified example in the pyroclastic vent NE of Rachmaninoff. Both examples show evidence of hollow sublimation being a cause of the mass movements

1:3M Geological Mapping of the Derain (H-10) Quadrangle of Mercury

We are making a high resolution geological map of the Derain quadrangle of Mercury. This is part of a coordinated project to create a global set of geological maps for BepiColombo

Benzylammonium 2,4-bis(dicyanomethylene)-2,3-dihydroisoindolide

The cation and anion of the title salt, C⁷H₁₀N⁺.C₁₄H₄N₅-, are both bisected by a crystallographic mirror plane. Extensive hydrogen bonding, with the R₆⁶(28) graph-set motif, connects the ions into layers

A Nest Trap for Snowy Plovers

A nest trap designed for ground nesting birds, specifically Snowy Plovers (Charadrius alexandrinus), is described. The trap is inexpensive to construct, easy to operate, and lightweight for ease of use under field conditions. The trap is designed to operate most efficiently under lightly or non-vegetated habitats, typical of Snowy Plover nesting sites

Avian Use of Chinese Tallow Seeds in Coastal Texas (Abstract)

The Chinese tallow tree (Sapium sebiferum) (Euphorbiaceae) was introduced into coastal Texas in the late 1800s and forms monotypic woodlands once naturalized. However, few studies have examined avian use of tallow seeds during fall migration in coastal Texas. We documented use of Chinese tallow seeds and compared foraging frequency on Chinese tallow seeds among permanent, summer, and winter residents and migrants. We also tested the hypothesis that Chinese tallow seed germination was enhanced by foraging activities of yellow-rumped warblers (Dendroica coronata), the most common species observed foraging on tallow seeds. During fall migration 1995 and 1996, 24 species were observed foraging on Chinese tallow seeds. Yellow-rumped warblers and Baltimore orioles (Icterus galbula) accounted for 72% of all tallow seed feeding observations. Winter residents foraged upon Chinese tallow seeds more frequently (P\u3c0.001) than summer residents, permanent residents, and migrants. Chinese tallow seed germination rates did not vary (P = 1.0) between seeds collected after yellow-rumped warbler feeding activities (2.5%) and those collected directly from seed bearing trees (2.5%). The high levels of fatty acids and oils in Chinese tallow seeds may be more important for winter residents than migrants or other groups of birds. Although germination is not enhanced by yellow-rumped warbler feeding activities, they may serve as dispersal agents, potentially enhancing future tallow expansion

Risk factors for house-entry by malaria vectors in a rural town and satellite villages in The Gambia.

Background: In the pre-intervention year of a randomized controlled trial investigating the protective effects of house screening against malaria-transmitting vectors, a multi-factorial risk factor analysis study was used to identify factors that influence mosquito house entry. Methods: Mosquitoes were sampled using CDC light traps in 976 houses, each on one night, in Farafenni town and surrounding villages during the malaria-transmission season in The Gambia. Catches from individual houses were both (a) left unadjusted and (b) adjusted relative to the number of mosquitoes caught in four sentinel houses that were operated nightly throughout the period, to allow for night-to-night variation. Houses were characterized by location, architecture, human occupancy and their mosquito control activities, and the number and type of domestic animals within the compound. Results: 106,536 mosquitoes were caught, of which 55% were Anopheles gambiae sensu lato, the major malaria vectors in the region. There were seven fold higher numbers of An. gambiae s.l. in the villages (geometric mean per trap night = 43.7, 95% confidence intervals, CIs = 39.5–48.4) than in Farafenni town (6.3, 5.7–7.2) and significant variation between residential blocks (p < 0.001). A negative binomial multivariate model performed equally well using unadjusted or adjusted trap data. Using the unadjusted data the presence of nuisance mosquitoes was reduced if the house was located in the town (odds ratio, OR = 0.11, 95% CIs = 0.09–0.13), the eaves were closed (OR = 0.71, 0.60–0.85), a horse was tethered near the house (OR = 0.77, 0.73–0.82), and churai, a local incense, was burned in the room at night (OR = 0.56, 0.47–0.66). Mosquito numbers increased per additional person in the house (OR = 1.04, 1.02–1.06) or trapping room (OR = 1.19, 1.13–1.25) and when the walls were made of mud blocks compared with concrete (OR = 1.44, 1.10–1.87). Conclusion: This study demonstrates that the risk of malaria transmission is greatest in rural areas, where large numbers of people sleep in houses made of mud blocks, where the eaves are open, horses are not tethered nearby and where churai is not burnt at night. These factors need to be considered in the design and analysis of intervention studies designed to reduce malaria transmission in The Gambia and other parts of sub-Saharan Africa